Electric fuel pump



APRZG, 1949 G. R. ERICSQN ZGSW ELECTRIC FUEL PUMP Filed Feb. 7, 1947 2 Sheets-Sheet l FBG WNVENTOR G- R. ERHCSGN ELECTRIC FUEL PUMP Ami@ 26p 2 sheets-sheet. 2

Filed Feb. 7, l94'7- INVENTOR Patented Apr. 26, 1949 ,UNITED STATES` PAT-ENT OFFICE ELECTRIC FUEL PUMP George R. Ericson, Kirkwood, Mo., asslgnor to Carter Carburetor Corporation, St. Louis, Mo., a corporation of Delaware Apncauon February 7, 1947, serial No. 727,117

claims. (ol. 10s-37) j This invention relates in general to liquid pumping apparatus, and has particular reference to certain improvements in a pump and drive motor unit adapted for operation submerged in a body or pool of liquid.

In Patent No. 2,394,860 to Alfred C. Korte, there is disclosed a centrifugal pump and motor assembly provided for operation submerged in a pool of volatile liquid, and embodying provisions for the circulation of liquid in the motor housing to afford lubrication of the motor bearings and a desirable degree of motor cooling. In the arrangement according to the patent, the motor housing normally is filled with liquid, so that the motor armature runs in a liquid bath, being comi pletely submerged therein. As a consequence thereof, the liquid bath imposes retarding forces on the armature in rotation, tending to increase the loading of the motor to an appreciable degree which, in practice, is found to be detrimental to a uniformly smooth operation of the motor.

Accordingly then, it is the principal object of the present invention to provide a pump and motor assembly which for the purpose of present example, may be of the general character shown in the aforesaid Korte patent, but which differstherefrom in the embodiment of certain improvements serving to avoid the above stated disadvantage. According to the presently improved purnp unit, liquid admission to the motor housing, aswell as liquid discharge therefrom, is confined to the lower` portion of the housing, while air, vapors andother gaseous matter are trapped and maintained under pressure in the greater part of the housing, so that at least a major extent of the motor armature will operate in a gaseous pocket rather than in a liquid bath. In accomplishing the foregoing, the present invention contemplates the provision of means preferably constituted by a pressure relief outlet suitably arranged near the lower end of the motor housing, which is effective in conjunction with the gaseous matter trapped in the housing and compressed in consequence of pressure circulation of liquid through the lower part of the housing, for determining and maintaining the liquid circulating through the housing, at a level therein below the major extent of the motor armature, yet at an elevation sufiicient to afford adequate pressure circulation of the liquid to maintain the motor commutator submerged in vliquid and to assure effective lubrication of the motor bearing. Moreover, while controlled as tothe liquid level thereof, the volume of liquid under pressure circulation in the lower zone of the motor housing, is fully sufficient for the absorption and removal of any excess of motor operating heat not conducted through the housing walls to the surrloundingliquid pool.

Other objects and advantages of the present invention'lwill appear'from the following description oiga'. presently preferred embodimentthereof, illustrated in the accompanying drawings, wherein: l

Fig. 1 is a sectional elevation vertically through a pump and motor unit embodying the present invention;

Fig. 24 is a side view of the lower part of the motor housing, with portions thereof shown in 1 section, the View including a part of the pump assembly, and

Fig. 3 is a top view of the lower part of the motor housing. L

In order to afford a clear illustration of the present improvements, the pump and motor unit shown, may be and by preference is, generally similar in construction and arrangement of parts, to the unit disclosed by the hereinabove mentioned Korte patent. As appears from the several figures of the drawings, the pump drive motor indicated as a whole by the reference numeral I0, is enclosed in a two-part housing comprised of an upper casting' II and a lower casting I2 suitably assembled, as through cooperating anges I 4 and I5 outstanding from the adjoining margins of the castings II and I2, respectively, and secured together by bolts (not shown). Upstanding from one side of the upper casting top wall IS is an apertured boss IB. Within the boss is a contact I9 which is yieldingly supported on a coil spring 20, the contactbeing connected to motor field 22 supported in the casting Il', by a wire 23 arranged in the motor housing and supported thereon in part, as at 24 .Y (Fig. l). A plug 26 supporting a complementary contact 21 which is connected to a motor current supply wire 28, is threaded into the boss to bring contacts I9 and 2l into firm electrical engagement. Importantly here for a purpose to appear. the plug 26 includes a sealing-sleeve 3D of suitable character, affording a liquid and air-tight seal at the boss, whereby to prevent leakage of liquid from the pond surrounding the unit, through the boss into the motor housing and conversely, leakage of gaseous matter outwardly through the boss from the housing interior. Although a sealing sleeve 30 is here utilized, it will be appreciated that the boss may be sealed in any other desired or well known manner.

Housing top wall I8 also includes a central bearingboss 8l providing an interior recess 82 having therein a Journal bearing 84 for the -upper end of the motor amature shaft 85. The boss is apertured at -88 outwardly from the recess 32, to receive a thrust screw 88 having a ball-end 39 in engagement with the upper terminal end 40 of the shaft 85, the thrust screw being adjustable from outside the casting. Externally threaded on the boss is a cap 42 within which is a sealing washer 48 for providing a fluid and' airtight closure of the apertured boss.

Lower housing casting I2 (Figs. 2 and 3) preferably is of generally conical shape, and is provided with external radial 'ribs 44 and'45 (Fig. 2) and similar ribs 48 and 41 (Fig. 1), each nib terminating in an apertured foot lug 48. The ribs 48 and 41 are extended interiorly of the conical casting wall 50, as at I and 52, respectively, on opposite sides of a circular wallportion 54 centrally opstanding on the wall 50 o1'. casting part I2. Each rib extension is provided with a horlzontal through-aperture 55 receiving therein one of the commutator brushes 56 and 58, the brushes in turn being constantly urged inwardly against the commutator 59 operatively located in the chamber S0 formed by circular wall 54, by

coil springs 62 one between each brush and a screw plug'63 closing the outer end of the brush aperture. I'he extension of rib 41 supports an insulated terminal lug 64 suitably electrically` connected to the brush 58 as shown in Fig. 1, and to which is connected a wire 66 leading from the motor eld 22. The opposite' brush 58 is'grounded to the casting I2. As appears in Fig. 1, the commutator chamber 68 is partly closed for the prevention of llame propagation, by a closure.- forming enlargement 61 on the motor armature, rotatable in the upper enlarged portion 68 of chamber 60. y

The interior space of the lower housing casting I2, extending about the central circular wall 54 thereof, provides a sediment sump and separating the sump space from the motor housing chamber 1I thereabove, is a iilter screen 12. Screenl 12 is maintained in assembly. preferably by clamping itsouter circumferential margin between the mating flanges of the housing castings, and securing its inner circular margin to a circular boss 14 integral with the wall 54, by suitable screws 15.

Motor shaft 35 isV projected downwardly through the lower housing casting I2 in the zone of chamber 60, for operative connection to the hub 16 of centrifugal impeller 18 in the pump assembly. A journal bearing 19 recessed in the bottom of chamber 69, rotatably supports the shaft. While the shaft and impeller are operatively supported in the vertical direction, by a foot bearing comprising a ball element'89 preferably seated in a recess 82 in the bottom side mais? of the impeller hub and bearing upon a plate According to the present exemplary disclosure,

aliquid pressure by-pass duct 82 (Fig. 2) open tothe discharge end of the pump volute chamber 88, as at 94, is provided in the rib 44 of the motor housing casting I2, the duct terminating in a jet nozzle 95 in the sump space 18 immediately below iilter screw 12. A portion o! the liquid under pressure discharge-by the pump, thus will be by-passed continuously duringpump operation, through the duct 92 to the lower zone of the motor housing assembly, the nozzle 95 being suitably ported such as to direct the liquid admission against the lter screen, thereby tending to keep the .screen clear of foreign matter. The liquid so admitted to the motor housing, circulates in the lower zone therein and over the upper edge of the wall 54 to and downwardly in the commutator chamber 60, to the motor shaft bearing 19, thus affording lubrication of the bearing 19 and maintaining the commutator submerged. From the region of bearing 19, the liquid is returned to the tank in which the pump unit is submerged, through ducts 98 provided in the ribs 46 and 41 (Fig. 1). Additionally, a duct 98 in rib 45 (Fig. 2) open at its lower end to the casing exterior, and at its upper end to the sump space 10, affords a drain for sediment accumulatingin the sump.

As before described, the apertured bosses at the upper end of the motor housing casting II are provided with uid tight seals, so that in the submerged position of the pump unit, gaseous matter above the liquid in motor chamber 1I will become trapped therein. Upon circulation of liquid through the lower zone of chamber 1I under a pressure determined according to the discharge pressure of the pump obtaining at the connection of the by-pass duct 92 to the discharge end of the volute chamber 88, the liquid in motor chamber 1i will tend to rise therein, compressing the trapped gaseous matter. Since it is desirable to aord liquid under ow-pressure in chamber 68 in order to assure a fully submerged condition of the commutator and adequate lubrication of the motor shaft bearing 19,

the liquid return capacity of the ducts 96 is limited to this end. N Gaseous bubbles which may be entrained in the liquid circulating through the motor housing, and vapor therefrom, will rise into the motor housing and add to the gaseous volume therein.

.A relief port I in the lower motor casing wall opens at its lower end HQE, to the motor chamber 1I below the armature, and is open at its upper end |83, to the tank outside the unit. 'I'he passage thus affords by-pass of a portion of the liquid under pressure circulation in the motor chamber 1l, directly to the tank from the lower end of the chamber in the zone above the screen 12. The by-pass capacity of the passage |98 is here predetermined as by selection of its sectional area, so that in normal operation of the pump unit, the rate of liquid discharge therethrough and through ducts 96 and 98 will be such as to establish and maintain a balance of thel liquid and gaseous pressures in the motor chamber 1I with the liquid level substantially asindicated by the line A--A (Fig. l), in a plane through the uppermost margin of the lower open end While the present improvements are here noi other types provided for submerged. operation.

Having now described the invention in respect to a presently preferred embodiment thereof as illustrated by the drawings, it is to be understood that the exclusive use of all modifications as come within the spirit and full intended scope of the appended claims is contemplated.

I claim:

1. In a pump assembly for operation` submerged in volatile liquid, an electric motor including a shaftl and armature, a housing receiving said motor with the shaft vertical therein, the upper part of said housing being fluid tight, a shaft bearing in the lower portion of said housing, receiving said shaft, a rotary pump below the housing operatively connected to said shaft, means for circulating fluid from said pump through said housing for lubricating said bearing, and a by-pass and pressure relief opening in the housing wall below the level of the lower portion of said armature and effective in cooperation with the pressure of vapors trapped in the casing upper portion during operation to determine a liquid level in the housing below the major portion of said armature.

2r In a liquid pump unit, a casing assembly providing separate, relatively spaced motor and pump chambers, an electric motor including a shaft, an armature thereon, and a lower shaft bearing, arranged in the motor chamber with the shaft extending therefrom toward the pump chamber, an impeller in the pump chamber operatively connected to the shaft extension, passage means connecting said pump and motor chambers to admit liquid to the motor chamber during pump operation, for lubricating said bearing, restricted passage means for discharging liquid from the lower portion of said bearing, and a liquid relief outlet in the lower wall of said motor chamber, the upper wall of said motor chamber being fluid tight whereby vapor and gases rising from the liquid in said motor chamber are trapped therein to the level of said relief outlet so that said armature normally operates in a gaseous atmosphere.

3. In a pump unit for operation submerged in liquid, a, casing assembly providing separate, vertically spaced motor and pump chambers, an electric motor including a shaft, an armature thereon, and a shaft bearing, arranged in the motor chamber with said bearing in the lower zone thereof. said shaft extending from the motor chamber toward the pump chamber, an impeller in the pump chamber operatively connected to the shaft extension, passage means for circulating liquid under pressure from the pump charnber to and through said lower zone of the motor chamber for lubricating said bearing, the upper wall of said motor chamberbeing sealed so as to trap gaseous matter above the liquid therein, the liquid under pressure in the motor chamber compressing said gaseous matter, and liquid and air outlet means spaced fromV said passage means', for relieving the liquid and excess gaseous matter from said motor chamber, said outlet means serving thereby and in cooperation with the gaseous matter compressed in the motor chamber, to determine in respect to the liquid circulating under pressure through the chamber, a liquid level thereof which is below the major portion v of the armature in the motor chamber.

4. A pumping unit for operation submerged in a body of liquid, comprising a casing assemblyv providing a motor chamber and a separate pump chamber therebelow, an electric motor including a shaft, an armature thereon, and a shaft bearing, arranged in the motor chamber with the shaft vertical and the shaft bearing in the lower wall of the chamber, an impeller in thev pump chamber and operatively connected to said shaft,

passage means extending from the pump chamber to and terminating above the lower end of said motor chamber, provided for yconducting liquid under pressure to the latter chamber for lubrication of said bearing, the upper wallof said motor chamber being fluid tight for trapping gaseous matter above the liquid therein, other passage means extending from the lower end portion of the motor chamber adjacent said bearing, to the casing exterior for the discharge of liquid, the liquid Yunder pressure in the motor chamber compressingv said gaseous matter therein, and means affording a liquid outlet communicating with the motor chamber in a zone thereof above the terminal end of the first said passage means, but below said armature and, serving in cooperation with the gaseous matter compressed in said motor chamber, to determine a liquid level therein which is below the major portion of said armature.

5. In a pumping unit for operation submerged in a body of vola-tile liquid, a motor housing, an electric motor therein including a shaft and an armature and -commutator thereon arranged vertically in the housing, and bearing means for the shaft, said bearing/means and commutator being disposed in a lower zone of said housing, a, pump adjacent the motor housing and including a pump impeller in driven connection with said motor shaft, means for circulating liquid under pressure from the pump through said lower zone of the housing and about said commutator and bearing means, the upper wall of said housing being fluid tight so as to trap gaseous matter rising from the liquid therein, and means comprising a passage communicating the housing interior with the body of liquid in which the pumping unit is submerged, arranged and adapted for by-passing a part of the liquid under pressure circulation in the housing and relieving excess gaseous matter from the housing, such as to determine and maintain a liquid level in the housing below the major portion of said armature therein.

.GEORGE R. ERICSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Korte Feb. 12, 1946 

